Study of the effect of electrolytes on the rheology of anionic polyacrylamide solutions
polymer rheology salinity cloud point
Loss of productivity in a well is a reality in the oil industry, where part of the oil present in the reservoir is not extracted by natural production methods. The implementation of chemical methods to increase efficiency in oil recovery is an economically viable alternative used by oil companies. One of the most used options is the injection of polymers, especially partially hydrolyzed polyacrylamide (HPAM), which promotes an increase in the viscosity of the injection water and, therefore, in the sweeping efficiency within the pores of the reservoir. In order to study the effect of inorganic salts on the polymer viscosity, rheological tests were performed using the HPAM 3430S with a molar mass of 12x106 Daltons in NaCl, KCl, MgCl2 and CaCl2 solutions, varying the temperature at 25, 40 and 55° W. It was observed that the salts promoted a severe reduction in viscosity along with the increase in temperature. The activation energy showed that at low shear rates, temperature is an influential factor in viscosity. The application of the Ostwald de Waele model proved that the increase in saline concentration made the solutions less pseudoplastic and with behavior closer to the Newtonian.